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Biomedical subjects

T Yagihara

Publications and source records attributed to T Yagihara.

At least 55 records · Page 3Linked to original sources
PubMed2000

Replacement of the tricuspid valve in children with congenital cardiac malformations.

BACKGROUND AND AIM OF THE STUDY: When replacing the regurgitant tricuspid valve in children, the decision to use either a bioprosthesis or a mechanical valve remains controversial. METHODS: The atrioventricular valve for the pulmonary circulation was replaced in 11 young patients aged between 8 months and 13 years. Complications of congenital cardiac malformation were present in seven patients, and Ebstein's anomaly in three; tricuspid valvular regurgitation was an isolated lesion in one patient. A bioprosthesis was implanted on seven occasions, and a bileaflet mechanical valve on eight, including re-replacement of the valve in four patients. RESULTS: One patient died two years after implantation due to respiratory problems. Tricuspid stenosis due to valve calcification occurred in four bioprostheses at between four and nine years after initial replacement (57%). In three of these cases the native valve leaflets had not been removed. Thrombosis occurred in one patient with a mechanical valve; rereplacement was successful. Anticoagulant-related hemorrhage occurred in another patient. Among patients receiving a mechanical valve, 83% of valves were dysfunction-free after five and ten years. CONCLUSION: When replacing an atrioventricular valve for the pulmonary circulation in children, we prefer to use a low-profile mechanical valve, especially when extensive repair of intracardiac malformation has been carried out, but ventricular function is good. In children with poor cardiac performance, a bioprosthesis is preferred, with total resection of the native valve leaflets.

Adolescent↗
PubMed1999

Comparison of the right and left ventricle as a systemic ventricle during exercise in patients with congenital heart disease.

BACKGROUND: Few studies have investigated the clinical advantages of surgical correction with the morphologic left ventricle (MLV) instead of the morphologic right ventricle as a systemic ventricle (SV) in patients with congenital heart disease. METHODS: Twenty-four healthy control subjects (group A1), 6 patients with isolated congenitally corrected transposition of the great arteries (TGA) (group A2), 16 patients with TGA who had undergone an arterial switch operation (group B1), 18 patients with TGA who had undergone a venous switch operation (group B2), 9 patients with atrioventricular and ventriculoarterial discordance who had undergone a double switch operation (group C1), and 6 patients with atrioventricular and ventriculoarterial discordance who had undergone a conventional external conduit operation from the MLV to the pulmonary artery (group C2), performed treadmill exercise testing. Their heart rate (HR), oxygen uptake (VO2), and oxygen pulse (O2 pulse), which reflects individual stroke volume, were measured, and contractile function was assessed by echocardiography. RESULTS: The peak HR for the patients after a definitive operation were significantly lower than that in group A1 and was correlated with peak VO2 (r =.67, P <.0001). The peak VO2 and peak O2 pulse for the groups A2 and B2 were significantly lower than those for the groups A1 and B1, respectively. The peak O2 pulse data were strongly correlated with those of peak VO 2 (r = 0.91, P <.0001). The left ventricular ejection fraction was significantly lower in groups B1 and C1 than in group A1 and was correlated with peak VO 2 (r =.50, P <.01). No significant differences in VO2, HR, and O 2 pulse at peak exercise were observed between groups C1 and C2. CONCLUSIONS: Chronotropic incompetence and an impaired response of the stroke volume of the MRV during exercise are partly responsible for the reduced exercise capacity in groups A2 and B2 compared with groups with the MLV as an SV, and the SV function at rest is also related to exercise capacity. Superiority of the double-switch operation compared with the conventional conduit operation was not observed. A longer-term follow-up is necessary before the advantages of these 2 operations can be compared.

Adolescent↗
PubMed1999

As originally published in 1992: new surgical technique for total-defect aortopulmonary window. Updated in 1999.

A new technique is described to repair aortopulmonary window with total defect in an 8-day-old baby. Because we expected the future growth of aorta, we used the anterior wall of the pulmonary artery as a large flap to reconstruct the posterolateral aortic wall. An equine pericardial patch was used to repair the defect in the pulmonary artery. This is a logically effective method for aortic reconstruction in a neonate with a large aortopulmonary septal defect.

Aortopulmonary Septal Defect↗
PubMed1999

Ventricular morphology and coronary arterial anatomy in hearts with isometric atrial appendages.

BACKGROUND: Knowledge of the precise anatomy can be advantageous when striving to improve surgical results in patients with visceral heterotaxy. METHODS: We studied the ventricular mass, and its coronary arterial supply, in 125 specimens with isomeric right and 58 with isomeric left appendages. RESULTS: The situation in which each atrium connected to its own ventricle was the most common arrangement in hearts with isomeric left appendages. The pattern with both atriums connecting to the same ventricle was more frequently seen in those with isomeric right appendages. Concordant ventriculoarterial connections were seen in only 4% of cases with isomeric right appendages, but were seen in 45% of those with isomeric left appendages. Abnormal patterns in branching of the coronary arteries were commonly associated with abnormal ventricular architecture. The morphologically right or left ventricular arteries were frequently lacking in those hearts with a dominant ventricle and a rudimentary and incomplete ventricle. A solitary coronary artery was seen in 13%. CONCLUSIONS: Recognition of these abnormalities is of clinical importance if optimal surgical strategies are to be established for patients with visceral heterotaxy.

Coronary Vessels↗
PubMed1999

Redirection of hepatic venous drainage after total cavopulmonary shunt in left isomerism.

BACKGROUND: Conversion from total cavopulmonary shunt (TCPS) to the Fontan circulation can improve cyanosis in patients with potential risks of development of pulmonary arteriovenous fistula (PAVF). METHODS: Inclusion of the hepatic veins in the pulmonary circulation was employed using an intra-atrial tube graft in 5 patients with left isomerism previously undergoing TCPS. Prior to the conversion, abnormal communication was identified between the azygos vein and either the hepatic or the portal vein in all. PAVF was seen in 3. RESULTS: All patients survived the procedure. Postoperative catheterization showed 13 +/- 2 mm Hg of superior caval venous pressure, and 2.3 +/- 0.4 L/min/m2 of cardiac index. Pulmonary arteriovenous fistula progressed markedly in the right lung even after the conversion in 2 patients, in whom the hepatic veins had been exclusively diverted to the left lung. Arterial oxygen saturation became below 65%, with exercise capacity reduced, in these 2 patients. The other patients remain asymptomatic. CONCLUSIONS: Total cavopulmonary shunt can be efficiently converted to the Fontan circulation by appropriately redirecting hepatic venous drainage to perfuse both lungs in a balanced fashion.

Aortography↗
PubMed1999

Use of expanded polytetrafluoroethylene sutures as artificial tendinous cords in children with congenital mitral regurgitation.

OBJECTIVE: To determine the efficacy in the intermediate term of artificial cords inserted in children with congenital mitral regurgitation. METHODS: We reconstructed the tendinous cords using expanded polytetrafluoroethylene (ePTFE) sutures in 11 children with severe mitral regurgitation. In these patients, the aortic (anterior) leaflet of the mitral valve had been markedly prolapsed, the tendinous cords being partially lacking in seven, and elongated in the remaining four. In addition, one of the papillary muscles was hypoplastic in five and absent in three. The number of artificial cords constructed varied from two to six. Conventional annuloplasty was performed in all to plicate the dilated annular attachment of the valve. Ventricular septal defect was present in four patients, and other associated malformations in another two. Age at operation ranged from 9 months to 9 years old, with a mean of 4.5 years. RESULTS: All patients survived the operation. No reoperation has been needed thus far. No complications were encountered related to the use of the prosthetic materials or anticoagulation. As judged by echocardiography, regurgitation became trivial or slight immediately after the repair. In two patients, however, regurgitation recurred within 1 year of the operation. Coaptation between the leaflets was maintained by a compensatory growth at the site of attachment of the artificial cords. Catheterization demonstrated significant improvements in the end-diastolic volume of the left ventricle. CONCLUSION: Expanded polytetrafluoroethylene sutures can be used as artificial cords when attempting to repair the malformed mitral valve in children, providing excellent results in the short- and the intermediate-term after the surgical procedure.

Child↗
PubMed1999

Ventricular outflow tracts after Kawashima intraventricular rerouting for double outlet right ventricle with subpulmonary ventricular septal defect.

OBJECTIVE: To determine whether or not the ventricular outflow tracts can be efficiently constructed in patients with double outlet right ventricle with subpulmonary ventricular septal defect by the Kawashima intraventricular rerouting in which the morphologically right ventricular outlet is divided into two, one for the systemic and the other for the pulmonary circulations. METHODS: The intraventricular rerouting procedure was carried out in nine patients with this particular malformation. Age at repair ranged from 35 days to 3 years old. The distance between the attachments of the tricuspid and the pulmonary valves was 10 mm or greater in all except one patient in whom the measured value was 3 mm. Resecting subaortic musculature appropriately, a tailored patch, either oval-shaped (in seven) or heart-shaped (in two), was placed to construct an unobstructed channel for the left ventricular outflow tract with its diameter greater than that of the anticipated normal aortic orifice at the time of repair. For an unobstructed channel to the pulmonary arteries, enlargement of the right ventricular outflow tract was carried out using a patch in six. RESULTS: All patients survived the operative procedure. On postoperative catheterization, mean pulmonary arterial pressure was 15 +/- 8 mmHg, and cardiac index was calculated as 3.3 +/- 0.6 l/min per m2. It proved that the constructed left ventricular outflow tract can become larger in the longer term. Pressure gradient across the left ventricular outflow tract was greater than 20 mmHg in two patients in the intermediate term. One of these two underwent reoperation for the obstruction 10 years after the initial repair. It was suspected that use of a heart-shaped internal conduit, which seems to result from inadequate conal resection, was one of the possible causes of such obstruction in the longer term. Pressure gradient of 47 mmHg was seen across the right ventricular outflow tract in one patient, although this patient has undergone no reoperation. Enlargement of the right ventricular outflow tract could minimize postoperative obstruction for the pulmonary pathway. CONCLUSIONS: The intraventricular rerouting remains one of the attractive surgical options for repair in this particular setting, in terms of successful construction of the ventricular outflow tracts.

Child, Preschool↗
PubMed1999

Two-dimensional electrophoresis of Malassezia allergens for atopic dermatitis and isolation of Mal f 4 homologs with mitochondrial malate dehydrogenase.

The yeast Malassezia furfur is a natural inhabitant of the human skin microflora that induces an allergic reaction in atopic dermatitis. To identify allergens of M. furfur, we separated a crude preparation of M. furfur antigens as discrete spots by 2-D PAGE and detected IgE-binding proteins using sera of atopic dermatitis patients. We identified the known allergens, Mal f 2 and Mal f 3, and determined N-terminal amino acid sequences of six new IgE-binding proteins including Mal f 4. The cDNA and genomic DNA encoding Mal f 4 were cloned and sequenced. The gene was mitochondrial malate dehydrogenase and encoded Mal f 4 composed of 315 amino acids and a signal sequence of 27 amino acids. We purified Mal f 4, which had a molecular mass of 35 kDa from a membrane fraction of a lysate of cultured cells. Thirty of 36 M. furfur-allergic atopic dermatitis patients (83.3%) had elevated serum levels of IgE to purified Mal f 4, indicating that Mal f 4 is a major allergen. There was a significant correlation of the Phadebas RAST unit values of Mal f 4 and the crude antigen, but not between Mal f 4 and the known allergen Mal f 2.

Allergens↗
PubMed1999

Re-replacement of the atrioventricular valve for the systemic circulation in children.

BACKGROUND AND AIM OF THE STUDY: The study aim was to determine whether re-replacement of the systemic atrioventricular (AV) valve can be achieved efficiently in children. METHODS: The systemic AV valve was re-replaced in 10 children. Initial replacement was needed for regurgitation in nine cases and congenital mitral stenosis in one case at a mean age of 3.7 +/- 3.1 years (range: 0.7-10.2 years). The initial prosthesis chosen was a mechanical valve in all cases; prosthesis size ranged from 16 mm to 27 mm. Reoperation was indicated at a mean age of 9.7 +/- 3.6 years (range: 3.5-14.8 years) because of non-structural dysfunction in five cases, prosthetic valve endocarditis in two, thrombosed valve in two, and progressive obstruction of the left ventricular outflow tract in one case. Fibrous tissues were extensively resected to enlarge the valvular orifice. A translocation maneuver was employed in five cases. RESULTS: Re-replacement using a bileaflet mechanical valve was successful, with no operative or late deaths. Up-sizing was feasible in six cases with the initial valve < or = 25 mm, the alternative prosthesis being 2-8 mm (mean 4.5 mm) larger than the initial one. Consecutive echocardiography demonstrated improved peak flow velocity across the AV valve (from 2.3 +/- 0.6 to 1.6 +/- 0.3 m/s). Catheterization showed improved mean pulmonary arterial pressure (from 32 +/- 13 to 21 +/- 3 mmHg). No change was seen in cardiac index (3.4 +/- 0.6 and 3.5 +/- 0.6 l/min/m2) or systemic ventricular ejection fraction (55 +/- 14% and 49 +/- 23%). CONCLUSIONS: Re-replacement of the systemic AV valve can be achieved efficiently, even in children, with up-sizing feasible by appropriate surgical maneuvers.

Adolescent↗
PubMed1999

Replacement of the morphologically tricuspid valve in children with discordant atrioventricular connections.

BACKGROUND AND AIM OF THE STUDY: Our clinical experience was reviewed to determine the efficacy of replacement of the atrioventricular (AV) valve for the systemic circulation in children with discordant AV connections undergoing functional biventricular repair. METHODS: Nine children underwent replacement of the morphologically tricuspid valve at the age of 10 months to 15 years. Ventriculoarterial connections were discordant in five children, and double outlet right ventricle with pulmonary stenosis or atresia in four. In all children the prosthesis chosen was a mechanical valve; valve sizes ranged from 19 mm to 31 mm. RESULTS: One patient died of ventricular failure immediately after surgery. Two patients underwent reoperation for re-replacement at eight and 68 months after the initial replacement because of non-structural dysfunction. Complete AV block occurred after intracardiac maneuvers in the non-survivor. Transient AV dissociation was noted in another patient. General conditions improved greatly after surgery in all survivors. In the morphologically right ventricle placed for the systemic circulation the end-diastolic volume fell from 327 +/- 182% (range: 109-621%) to 169 +/- 97% (range: 85-352%) of the anticipated normal value (p = 0.03), while pressure fell from 13 +/- 4 (range: 7-19) mmHg to 8 +/- 3 (range: 2-12) mmHg (p = 0.005). The ejection fraction was only marginally reduced (47 +/- 13% (range: 26-62%) preoperatively versus 34 +/- 11% (range: 20-54%) postoperatively; p = 0.13). CONCLUSIONS: In children with discordant atrioventricular connections and severe regurgitation across the morphologically tricuspid valve, the valve can be efficiently replaced for the systemic circulation.

Adolescent↗
PubMed1998

[A successful biventricular repair in an adult case with "common ventricle" and isomeric atrial appendages previously undergoing the conventional Glenn procedure].

We describe herein a successful biventricular repair in a 21-year-old male who had severe hypoplasia of isomeric right appendages. He had previously undergone the conventional Glenn procedure at the age of one and a half years. Although he had grown uneventfully until adolescence, cyanosis as well as fatigue than gradually became worse. When referred to us for further treatment, we deemed a Fontan type procedure to be contraindicated, because of the hypoplastic nature of the right pulmonary artery, and the presence of abundant collateral arteries supplying the right lung. In terms of ventricular morphology, however, because both apical components were present, separated by the hypoplastic septum, biventricular repair seemed feasible. Initially, the Glenn anastomosis was taken down, and systemic-to-pulmonary shunts were constructed via a median sternotomy to both the right and left pulmonary arteries. This was followed by surgical division of the developed collaterals to the right lung via the right thoracotomy. Definitive biventricular repair was then carried out by reconstructing the pulmonary arteries and right ventricular outflow tact, separating and rerouting within the ventricles using a EPTFE patch, and achieving redirection of blood within the atriums using bovine pericardium. Such staged surgical approaches, although extensive, can provide useful options when seeking definitive repair in grown-up patients with complicated malformations.

Adult↗
PubMed1998

[Long-term results of aortic root replacements with pulmonary autografts (Ross procedure) in five cases].

Aortic root replacement with a pulmonary autograft (the Ross Procedure) has been successfully performed in our hospital since November, 1992. The long-term results of five of the earliest cases are reported in this paper (2-3 year follow-up). The patients' ages were two months to eighteen years old. Four of the patients suffered from aortic valve stenosis, and one suffered from aortic regurgitation. Severe left ventricular failure was recognized in three cases. However, the patients recovered from surgery smoothly and without significant aortic regurgitation and left ventricular outflow tract gradients. A serious concern exist as to whether the implanted autograft in 2 months old infant would grow. In this patient, postoperative cardiac catheterization was performed after sixty days, one year, and two years. The diameter of the anulus of the pulmonary autograft enlarged from 12 mm to 18 mm over the period of two years. Compared with the calculated aortic valvular diameter from a standardized body surface area, these diameters were equivalent to 150%-162% of the standardized size at each age. The implanted pulmonary autograft has subsequently enlarged gradually and proportionally. Its function as an aortic valve was maintained even after significant enlargement of the aortic anulus to 18 mm. We therefore conclude that the Ross procedure can be recommended because of the apparent ability the pulmonary autograft to grow over time.

Adolescent↗
PubMed1998

Artificial chordae for mitral valve reconstruction in children.

BACKGROUND: Congenital mitral regurgitation continues to present a challenge for cardiac surgeons because of the diversity of the anatomy of the congenitally malformed mitral valve. We undertook aggressive repair of the mitral valve with artificial chordae for reconstruction of the prolapsed anterior leaflet in some children. The short-term results are reported herein. METHODS: Three patients with isolated congenital mitral regurgitation underwent mitral valve repair with use of expanded polytetrafluoroethylene sutures as artificial chordae. RESULTS: There have been no late deaths and no valve-related complications. Serial follow-up echocardiographic examinations have not revealed any increase in the severity of mitral regurgitation with continuing patient growth up to 39 months after the operation. CONCLUSIONS: When combined with other conservative methods of mitral valve repair, chordal replacement with expanded polytetrafluoroethylene sutures in children undergoing mitral valve reconstruction produces good short-term results. We believe that it delays and possibly prevents the need for a mechanical prosthesis with its associated complications in this young patient population.

Cardiac Volume↗
PubMed1998

Establishment of total cavopulmonary connection without use of cardiopulmonary bypass.

OBJECTIVE: To minimize deleterious postoperative influences of cardiopulmonary bypass on the pulmonary circulation immediately after the Fontan type procedure, total cavopulmonary connection was achieved without use of cardiopulmonary bypass. METHODS: Since April 1996, 15 patients including five patients with visceral heterotaxy, in whom no intracardiac procedure was needed, have undergone this operative maneuver. Age at operation ranged from 1.2 to 44.6 years. Construction of a systemic to pulmonary shunt had been previously employed in seven patients, banding of the pulmonary trunk in two patients, and the Norwood procedure in one patient. The superior caval vein was initially anastomosed to the pulmonary arteries in bidirectional fashion under temporary bypass from the superior caval vein to the atrium. The channel for draining the inferior caval vein was subsequently constructed with the aid of temporary bypass from the inferior caval vein to the atrium, using a Goretex tube in ten patients, using a pedicled autologous pericardial roll in four patients, and directly anastomosing the pulmonary trunk to the orifice of the inferior caval vein in one patient. In patients with visceral heterotaxy and an independent hepatic venous drainage, redirection of the blood flow via the caval vein as well as the hepatic vein could be successfully achieved by placing dual temporary bypasses into these veins. RESULTS: Postoperative courses were excellent in all patients. Superior caval venous pressure was 11 +/- 2 mmHg at 12 h after the operation. No blood transfusion was needed in nine patients(60%). CONCLUSION: This alternative operative procedure is undoubtedly attractive when establishing the Fontan circulation in patients undergoing no intracardiac maneuvers.

Adolescent↗
PubMed1998

The structure of the common atrioventricular valve in hearts having isomeric atrial appendages and double inlet ventricle.

BACKGROUND AND AIMS OF THE STUDY: It is now well recognized that regurgitation through a common atrioventricular valve can compromise the clinical course both before and after surgical interventions in patients with visceral heterotaxy. This may reflect the anatomic structure of the valve. This study aimed to determine whether the structure of the common atrioventricular valve found in the setting of hearts with isomeric atrial appendages and double inlet ventricle differs from that of the valve guarding a common junction in hearts with biventricular atrioventricular connections. METHODS: Sixty-three autopsied hearts with double inlet ventricle and isomeric atrial appendages were studied, in addition to 79 with isomerism and biventricular atrioventricular connections, all having a common valve guarding the atrioventricular junctions. RESULTS: A valve with three or four leaflets was seen more frequently in hearts with double inlet ventricle than in those with biventricular atrioventricular connections (p = 0.016, chi-squared test). Complicated multiple orifices within the valvular curtain, including abnormal accessory orifices within a leaflet, were found in seven cases with double inlet to a dominant morphologically left or right ventricle. The presence of four papillary muscles was the most common pattern in hearts with double inlet ventricle. Straddling of the papillary muscles to a rudimentary and incomplete ventricle was seen in 23% of cases. Direct attachment of tendinous cords to the ventricular septum or parietal wall was seen 81% of hearts with double inlet. CONCLUSIONS: These features of the common valve found with double inlet atrioventricular connection seem less suited to function as the inlet valve supporting the systemic circulation. The recognized abnormal features should be identified preoperatively so as to plan more effective valvular plasty, or alternatively to establish different surgical strategies.

Abnormalities, Multiple↗
PubMed1997

Cardiorespiratory responses to exercise after repair of the univentricular heart.

The purpose of this study is to evaluate cardiorespiratory responses to exercise in patients with univentricular heart according to the type of repair used. Forty-three patients with univentricular heart were divided into three groups: 15 preoperative patients (group A), 18 who had Fontan repair (group B) and 10 who had ventricular septation (group C). Group C was further divided into two subgroups, 7 with normal atrioventricular valve function (group C1) and 3 with atrioventricular valve regurgitation (group C2). Cardiorespiratory variables were determined after performance of cardiopulmonary exercise testing. One-hundred-and-twenty-five healthy subjects, age 5-26 years, served as controls. Oxygen uptake in group C1 at both ventilatory threshold and peak exercise was highest in all groups of univentricular heart (P < 0.05), while peak oxygen uptake in group C1 was significantly lower vs controls (P < 0.001), and that in group B was significantly higher than that for group A. Although chronotropic incompetence was noted in all groups of univentricular heart, marked improvements in both the relationship between heart rate and oxygen uptake and in the ventilatory efficiency were observed after definitive repair. While ventilatory efficiency was still impaired in group B, there was no significant difference between that in group C1 and the control group. When patients with univentricular heart of the left ventricular type (Van Praagh's type A single ventricle) were analyzed separately, superior cardiorespiratory response after ventricular septation was also found. In view of these findings, the ventricular septation procedure is preferred to the Fontan method in patients with univentricular heart when morphological conditions are suitable for this procedure so as not to make residual complications, such as significant atrioventricular valve regurgitation.

Adolescent↗